In an injection-molded mesh filter, a mesh member for filtering out a foreign substance from a fluid includes: a plurality of horizontal bars; a plurality of vertical bars perpendicular to the horizontal bars; and a rectangular opening defined by an adjacent pair of horizontal bars and an adjacent pair of vertical bars. The horizontal bars and the vertical bars have a substantially ellipsoidal cross-sectional shape. Also, the opening is formed of smooth side faces of the adjacent pair of horizontal bars and smooth side faces of the adjacent pair of vertical bars and the opening at the upstream side of the fluid flow direction flows the fluid in a smoothly-squeezing manner, and the opening at downstream side of the fluid flow direction flows the fluid in a smoothly-expanding manner.